Metacognitive therapy is an effective treatment for anxiety disorders in adults. Studies have demonstrated that the underlying theoretical model is also supported in children. It has therefore been suggested that metacognitive therapy for children may be effective. Our study is an open trial of metacognitive therapy for children with generalized anxiety as their primary disorder. Therapy was provided in groups. Families were interviewed with the Anxiety Disorders Interview Schedule - child/parent versions. They reported on the child's anxiety levels using the Revised Childrens Anxiety and Depression Scale - child/parent versions. Children reported on metacognitive beliefs using the Metacognitions Questionnaire for Children - 30 item version. Fourty-four children aged 7-13 years (50% girls) were enrolled, and one family dropped out during treatment. Fifty percent of the children had received counseling or psychological treatment for their anxiety disorder previously. Following treatment, 86.4% of the children were free of their primary disorder and 72.7% were free of all anxiety disorders, the corresponding figures were 75% and 65.9% at 6-months follow-up. The effect sizes were large for all measures and clinically significant improvements were obtained for 70% of the children at posttest and 77% at follow-up. Our study suggests that metacognitive therapy for children with generalized anxiety disorder may be a highly promising treatment approach.